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Biomedical subjects

H Maeda

Publications and source records attributed to H Maeda.

At least 1,441 records · Page 80Linked to original sources
PubMed1976

Effects of psychotropic drugs upon the hypothalamic rage response in cats.

Effects of Chlorpromazine (CPZ), Haloperidol (HLP), Pentobarbital (PTB), and Diazepam (DZP) upon thresholds of the hypothalamically elicited rage response, i.e., directed attack and treat responses, were studied in chronic cats. All these drugs elevated the directed attack thresholds. CPZ and HLP elevated also the threat response thresholds and produced ataxia, but DZP did not show these effects. From these results, it is suggested that CPA and HLP suppressed the amygdalo-ventromedial hypothalamic nuclear and cerebellar functions and DZP suppressed the afferent pathway of the direct attack. PTB showed intermediate effects between the above two groups.

Anger↗
PubMed1976

Quantitative and qualitative determinations of the combined effect of tetracycline and oleandomycin. I. In vitro effect.

Growth inhibitory effect of combined treatment of tetracycline (TC) and oleandomycin (OM), at a ratio of 2:1, on certain species of pathogenic bacteria including drug-resistant ones was examined. By the crossed paper strip method, synergistic effects were demonstrated against 9 of the 16 strains of Staphylococcus aureus, and all of the 5 strains of Escherichia coli studied. Antagonism was observed with none of the strains and with 2 strains of Streptococcus pyogenes and 2 strains of Streptococcus pneumoniae tested in the present experiments. The MICs determined by the agar dilution method, also gave similar results, although synergism was not conclusively demonstrated by this method. With representative strains of S. aureus, synergism was evidenced by quantitative measurement of growth inhibition. In some strains, 1.0 mug of one drug per ml of medium inhibited the induction of resistance to the second drug. Such a small dose of one drug also inhibited the development of a mutant resistant to the second drug. These inhibitory actions were thought to be one of the important factors causing the synergistic effect of TC and OM on drug resistant bacteria.

Drug Combinations↗
PubMed1975

Subcellular fate of protein antibiotic neocarzinostatin in culture of a lymphoid cell line from Burkitt's lymphoma.

14C-LABELED PROTEIN ANTIBIOTIC NEOCARZINOSTATIN (NCS) was prepared efficiently by chemical modification. With the use of lymphoma-derived cell line P3HR-1, the subcellular behavior of this antitumor antibiotic was studied by the uptake a. nd autoradiography of isolated nuclei of radioactive NCS. The antibiotic was taken up by the cells, reaching the maximum value at 1.5 hr and decreasing in value at 4.0 hr to the level at 0.5 hr. The silver grains in the autoradiograms were also found in the isolated nuclei. The grain count in the nuclei showed a tendency similar to the uptake of NCS by the whole cells, i.e., a gradual increase at 0.5 hr, reaching the maximum value at 1.5 hr, and then decreasing after 4.0 hr to the level at 0.5 hr. These facts indicated that NCS reached not only to cytosol but also into the nucleus, and/or at least to the nuclear membrane of the lymphoid cell. The number of NCS molecules incorporated into the cells at 1.5 hr was calculated to be about 1 x 10-6/cells at a concentration of 3 mug NCS per ml of medium, which can be extrapolated to 1 x 10-4 molecules per cell at the minimum inhibitory concentration. The number of molecules should be even less within the nucleus. In cell-free systems, the interaction of DNA and NCS, which is an inhibitor of DNA synthesis, was investigated with use of a Sephadex G-100 column, with negative results. In the cell culture system, NCS molecules were degraded into smaller polypeptides of certain sizes by proteolysis either by serum component(s) or by cells themselves. An inactive isomer, pre-NCS, which is an antagonist of NCS and a partially denatured homologous molecule, behaved similarly to NCS in all of these experiments. Because the chemically modified NCS used in this study retained biological activity essentially similar to that of parental NCS, the results obtained here could be interpreted as similar to those of parental NCS in vitro.

Antibiotics, Antineoplastic↗